Embodiments herein relate to processes for preparing a polyester resin as a toner production component and processes for preparing a toner composition that include preparing a polyester resin. Some embodiments are drawn to processes for producing a toner production component or a toner composition, including recycling a carbon dioxide byproduct.
Polyester and unsaturated polyester resins can be prepared by a polycondensation process involving the reaction of a diol and a diacid or diester. Unsaturated polyester resins can be prepared using an unsaturated diacid containing an alkene segment, such as fumaric or maleic acid or diesters thereof.
Commercially available electrophotographic toners can comprise a resin, such as a polyester, a pigment and optionally a charge control agent. Many different toner formulations are known. Some toner formulations that provide desirable low fixing temperatures and offset properties comprise a crosslinked unsaturated polyester resin. U.S. Pat. No. 5,227,460 discloses examples of such toner formulations and its disclosure is incorporated herein by reference in its entirety.
Unsaturated polyester resins can be obtained by a condensation method of alkoxylation that can include the reaction of a diol with a cyclic alkylene carbonate. In a specific example, bisphenol A can be condensed with a cyclic propylene carbonate in the presence of a catalyst, thereby releasing carbon dioxide as a byproduct and producing a mixture of propoxylated bisphenol A. The source of the carbon dioxide is the propylene carbonate (cyclic alkylene carbonate).
Because toners are used in such great quantities worldwide, recycling the CO2 produced as a byproduct of preparing polyester resins used in the toners may reduce the amount of CO2 released into the environment. The carbon dioxide can be sequestered or collected for recycling. However, it is very costly to liquefy/solidify and re-transport CO2. There is a need to minimize the amount of carbon dioxide generated and released to the atmosphere. There is also a need to lower the cost of resin processes involved in the production of polyesters, such as unsaturated polyesters used in the production of toners.